<template>
  <div>
    <!-- 无id时, 可以使用index(反正也是就地更新) -->
    <div
      style="display: inline-block"
    >
      
      <span v-for="(item,index) in arr" :key="index"><input type="checkbox" :value="item" v-model="newarr"/>{{ item }}</span>
    </div>
    <p>你选中的元素, 累加的值和为: {{sum}}</p>
  </div>
</template>

<script>
export default {
  data() {
    return {
      arr: [9, 15, 19, 25, 29, 31, 48, 57, 62, 79, 87],
      newarr:[]
    };
  },
  computed:{
    sum(){
      return this.newarr.reduce((sum, item) => sum + item, 0);
    }
  }
};
</script>